The dilatation of arteries was first recognized as a disease of the cardiovascular system in Egypt in the 1550s bc, and the first to describe an abdominal aortic aneurysm was the Flemish physician Vesalius about three millennia later in 1555. Two centuries later, in 1785, the English surgeon John Hunter began to treat aneurysms of the peripheral vessels by ligation.¹ Hunter ligated the superficial femoral artery, causing a patient’s popliteal aneurysm to slowly decrease in size over several weeks. Before this procedure, the options for treating such a popliteal aneurysm were to either wait for rupture or to prophylactically amputate the extremity.² The first attempt at percutaneous endovascular aneurysm repair was commenced by Moore and Muchison in 1864, in which a patient with a thoracic aortic aneurysm had an aneurysm cannulated and packed with a couple dozen yards of wire coils in hopes of inducing thrombosis. While the patient died, the aneurysm was noted to have partially thrombosed.³ Accompanied by the advancement of other therapeutic modalities, in 1948, Dr. Rudolph Nissen in New York used a cellophane wrap to treat aortic aneurysms. One of the greatest scientific minds of the 20th century experienced a thoracic aortic aneurysm and was treated by Nissen: in December 1948, Albert Einstein underwent surgery for a large thoracic aortic aneurysm, and Nissen performed the procedure. He was, however, only able to wrap the anterior portion of the aneurysm with cellophane, as aortic mobilization was generally considered to be forbidden at the time. The treatment was partially effective, but despite Nissen’s best efforts, Einstein died of a ruptured aneurysm 6 years later at the age of 76 years.⁴

In 1951, Dr. Charles Dubost in Paris performed the first successful resection of an abdominal aortic aneurysm, using a 15 cm long cadaver aortic homograft.⁵ After this development, a new era in the surgical treatment of aortic aneurysms was launched along with the introduction and clinical application of cardiopulmonary bypass (CPB) by John Gibbon in 1953. These developments facilitated the application of various surgical techniques required for the reconstruction of the ascending aorta, including the use of aortic allografts as an aortic replacement. In the mid-1950s, other major milestones in open heart surgery were also taking place, such as the first open-heart repairs of ventricular septal defect, atrioventricular communis, and tetralogy of Fallot. Such procedures used extracorporeal cross-circulation.^6–10

Later, a combined operation to replace the ascending thoracic aortic aneurysm, as well as the aortic valve along with the reimplantation of the coronary arteries was performed by Hugh Bentall and Antony De Bono in 1968,^11,12 and around this time, Dacron was introduced by Dr. Michael DeBakey.¹³ Interestingly, DeBakey, himself a pioneering cardiac surgeon, was affected by an aortic aneurysm when he was 97 years old. He was at home while preparing a medicine lecture when he experienced symptoms that he himself recognized as those of an acute thoracic aortic aneurysm dissection. He initially refused anesthesia and surgery, but his situation deteriorated, and his wife demanded that her husband have surgery. The Ethics Committee at Methodist Hospital in Houston, Texas approved the planned surgery. His postoperative recovery was prolonged and complex. In retrospect, Dr. DeBakey publicly acknowledged that he was happy that he underwent the surgical procedure. He died of natural causes shortly before his 100th birthday in July, 2008.¹⁴

In the decades following DeBakey’s accomplishments, developments in the realm of thoracic aortic aneurysm repair commenced. The use of one-lung ventilation (OLV) was first described by Dr. Eric Carlens, who introduced the double-lumen endobronchial tube.¹⁵ Dr. Irving Sarot, a thoracic surgeon at the Mount Sinai Hospital, started to use the same technique in 1971.

Dr. Randall Griepp, who later became the chairman of cardiothoracic surgery at the Mount Sinai Hospital, developed the use of deep hypothermic circulatory arrest in the repair of ascending thoracic aortic aneurysms while at Stanford University Hospital. Griepp explained that “a combination of surface cooling and CPB was used to produce total body hypothermia,” and subsequently “CPB was then used to warm the patient and resuscitate the heart.”¹⁶ A timeline incorporating some of the most significant events pertaining to aortic aneurysms can be seen in Fig. 39.1, including the first successful endovascular aneurysm repair, which occurred in 1990, and the first successful thoracic endovascular aortic repair, which took place in 1992.

The repair of a thoracic aortic aneurysm is now a daily practice in cardiac surgery, and management of such cases presents challenges in the domains of anesthesia, analgesia, ventilation, perfusion, monitoring, and the surgical procedure itself.^17,18 Major milestones in the development of the contemporary clinical paradigm of the management of thoracic aortic aneurysms have included OLV, CPB, hemodilution, hypothermic circulatory arrest, cerebral perfusion, as well as advances in anesthesia, pharmacology, and monitoring, including echocardiography and cerebral oximetry.¹⁹ These multiple advances in surgery and anesthesia facilitated the development and practice of techniques for the reconstruction of the ascending aorta and aortic arch following a dissection.^5,6,20

Marfan Syndrome: History and Importance

Marfan syndrome is a common genetic disorder that holds implications for thoracic aortic disease.²¹ The condition affects around one in 5000 people and will most likely be seen by almost all anesthesiologists during their careers. The specific mutation in Marfan syndrome is in the gene encoding the fibrillin-1 protein, a significant component of the extracellular matrix. It was previously believed that an abnormal fibrillin-1 protein decreased the strength of the extracellular matrix in tissue, such as the aortic wall, causing patients to have abnormal elasticity in the aortic wall and predisposing to dilatation.²² Interestingly, newer evidence suggests instead that aberrant signaling pathways lead to the degeneration of the aortic wall matrix. It is thought that transforming growth factor beta (TGF-β) is particularly affected by abnormal fibrillin. In fact, the inhibition of TGF-β in these mouse models largely reverses phenotypic and pathologic disease manifestations.²³ The physical manifestations of Marfan syndrome are well-documented and include joint hypermobility, a tall, lean stature, high palate, ocular disorders, mitral valve prolapse, and aortic root dilatation. The most common cause of death in patients with Marfan syndrome is complications involving the aorta.²⁴ It is not uncommon for patients to be totally unaware that they have Marfan syndrome until they present with an acute aortic event.

The first description of Marfan syndrome was presented by French pediatrician Antonin-Bernard Jean Marfan at the Société Médicale des Hôpitaux de Paris on February 28, 1896 in a presentation entitled, “Un cas de deformation congénitale des quatre membres, plus prononcée aux extrémités, caractérisée par l’allongement des os avec un certain degré d’amincissement” (roughly translated as “a case of congenital deformation of the four limbs, more pronounced at the extremities, characterized by the elongation of the bones with a certain degree of thinning”).²⁵ The presentation discussed multiple joint contractures, as well as scoliosis and abnormally long and thin limbs and fingers in a 5-year-old girl.

In 1901, Mery and Babonneix used the newly discovered tool of x-rays to further investigate this pathology. They presented newly observed skeletal features at the Société Médicale des Hôpitaux de Paris, documenting x-ray findings of the same patient described by Antonin-Bernard Jean Marfan, noting that the bones showed dévelopement hypertrophié des cartilages, or the development of hypertrophied cartilages.²⁶ In 1938, the patient died of tuberculosis, and no cardiac or ocular findings were mentioned. Although it is unclear whether or not this small girl actually had what would now be referred to as Marfan syndrome, she indeed had congenital contractual arachnodactyly.²⁷

Descriptions further elucidating Marfan syndrome came into the literature over the next several years. A patient with hypogonadism and dolichostenomelia (i.e., lengthy limbs), in addition to mobile joints in the hands, was soon described, and his presentation was used to better characterize the condition. Also ectopia lentis (i.e., subluxation of the ocular lenses) was described in tandem with disproportionately lengthy limbs in 1914, and an association between these physical traits and hereditability was made in 1931, when Weve described distrophia mesodermalis congenita, typus Marfanis.^28,29 The following decade, dolichostenomelia was associated with mitral valve degeneration and aortic root dissection. The connection between aortic root dissection and skeletal abnormalities was made by Baer and colleagues in 1943,³⁰ and the associations between skeletal, ocular, and aortic pathologies in Marfan syndrome have since been a cornerstone in its diagnosis.³¹

It was not until 1986 that the connective tissue glycoprotein (fibrillin) was isolated from human fibroblast cell cultures. It was determined that this glycoprotein was ubiquitous throughout the human body, composing significant portions of the extracellular matrix in skin, tendons, cartilage, cardiac valves, lungs, kidneys, muscle, and corneas.³² In 1991, the gene linked to Marfan disease, fibrillin-1(FBN1), was ultimately uncovered by researchers at the Mount Sinai Medical Center in New York City.³³ This gene structure was subsequently characterized, and these discoveries contributed to the currently available genetic testing for the diagnosis of Marfan syndrome.³⁴

Thoracic Aortic Aneurysms: Prevalence, Significance, and Complications

Thoracic aortic aneurysms are oftentimes silent until catastrophe strikes, and almost 95% of patients with thoracic aortic aneurysms are undiagnosed and totally unaware of their condition.^35,36 The management of thoracic aortic aneurysms remains challenging in both the elective and emergent settings.³⁷ The mortality of ruptured thoracic aortic aneurysms approaches 100%,³⁸ and it can be a difficult decision whether or not to operate on a thoracic aortic dissection once it has been discovered. Clinician opinions differ on when to initiate aggressive surgical procedures, and these decisions hold tremendous consequences for patients. It is highly probable that reported incidences of thoracic aortic aneurysms are underestimates, as fatal thoracic aortic aneurysm ruptures can be misdiagnosed as myocardial infarctions.^39,40 No two thoracic aortic aneurysms are the same, and it is critical to understand the etiology and management of this phenomenon.¹¹ Historically, the only treatment option for aortic arch disease has been open arch replacement under circulatory arrest conditions with or without selective cerebral perfusion. However, this open procedure has significant morbidity and mortality, especially in elderly patients with multiple comorbidities. To potentially mitigate the risks associated with open aortic arch replacement, endovascular arch repair has gained momentum as an alternative treatment option. Currently, efforts to stent the aortic arch are being trialed in numerous international healthcare facilities around the world. Patients selected for this procedure are considered high risk for conventional open arch replacement.⁴¹

Thoracic aortic aneurysms affect more than 15,000 people in the United States every year, and around 60% of all thoracic aortic aneurysms are in the ascending aorta. One of the principal causes of death because of thoracic aortic aneurysms is a dissection, or a tear in the wall of the aorta, as well as total rupture. Type A aortic dissection (TAAD), for example, is specified in the Stanford classification as a dissection of the ascending aorta, regardless of the distal extent of the tear, whereas type B dissection involves the lower aorta. Overall, pooled hospital mortality from a recent systematic review and metaanalysis demonstrated that hospital mortality for all surgical repairs of TAAD was 11.9%.^42,43 Etiologies of TAAD include hypertension, atherosclerosis, connective tissue disorders, trauma, infection, and previous cardiac or vascular surgery. The inherited disorders associated with TAAD include aortopathies associated with Marfan syndrome, Ehlers-Danlos syndrome, Loeys-Dietz syndrome, and the bicuspid aortic valve.⁴⁴ Examples of other such conditions that serve as a differential diagnosis for Marfan syndrome can be seen in Box 39.1. The revised Ghent criteria for the diagnosis of Marfan syndrome in adults is found in Box 39.2. An artistic illustration of a thoracic aortic aneurysm is presented in Fig. 39.2. In addition, a computed tomography (CT) angiography of an aneurysmal thoracic aorta in Marfan syndrome is seen in Fig. 39.3.